Dell PowerEdge C8000 Hardware Owner's Manual page 16

The figure below shows a single path connection from single-RAID HBA
compute sled to two cascaded storage sleds. In this mode, the hard-drives
in the two storage sleds are cascaded for extended storage capacity.
Figure 1-10. Single Host to Cascaded Storage Sled Connection
Storage Sled 2
16
About Your System
Storage Sled 1
Port 1
Port 2
Single-RAID
Compute Sled